Iron railway-bridge.



10.737,67'9. PATBNTED SEPT. 1, 1903'. J. A. L. WADDBLL sz I. G. HEDRIGK.

IRON RAILWAY BRIDGE.

APPLIOATION FILED Nov. 5, 1902.

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IRON RAILWAY BRIDGE.

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UNITED STATES Patented September 1, 1903.

PATENT OFFICE.

JOHN ALEXANDER LOW WADDELL AND IRA GRAN-T HEDRIOK, OF KANSAS CITY, MISSOURI.

IRON RAILWAY-BRIDGE.

SPECIFICATION forming part of Letters Patent No. '737,67' 9, dated September 1, 1903.

Application filed November 5,1902. Serial No. 130.151.4 (No model.)

To a/ZZ whom t may concern:

Be it known that we, JOHN ALEXANDER LOW IVADDELL, civil engineer, residing at 2708 Forest avenue, and IRA GRANT HEDRICK,

civil engineer, residing at 2216 East Eighth street, Kansas City, in the State of Missouri, both citizens of the United States, doing business as consulting engineers at the new Nelson Block, in said city, have invented an Iinxo provenient in Iron Railway-Bridges, of which the following is a specification.

In those cases where new railroads are built requiring only a single track at first, but destined ultimately to be provided with a double track, a large part of the expense of making the change from single to double track is involved in substituting double-track for singletrack bridges. On the other hand, if doubletrack bridges are built in the first instance zo the additional expense thereof as compared with sin gie-track structures will breed a large loss in the forni of interest charges during the years elapsing between their first building and the time when double track is finally z 5 laid.

It is the object of this invention to provide two forms of bridge so related that one will serve as a single-track bridge, but may be converted into the second forin for carrying 3o a double track at very little greater final outlay than if the double-track bridge had been originally built. At the saine time the singletrack forin costs but little inore than an ordinary single-track structure, and thus nearly 3 5 the entire extra interest charge, otherwise lost, will be saved. Moreover, the change from single to double track takes far less time than is involved in other and prior methods.

Our invention is illustrated in the accompanying drawings, wherein- Figure l is a transverse vertical section of both forms of bridge. Fig. 2 is in part a top View and in part a horizont-al section of' Fig. l with tracks and ties removed. Figs. 3, 4,

and 5 are details of joints and fastenings on a larger scale.

In Fig. l the first or single-track form of bridge is shown in full lines, forming a part 5o of the entire or second forni of bridge, the

additional parts of which are shown in dotted lines. In the first or single-track form of bridge the vertical trusses are shown at l and the horizontal cross-trusses at 2. The

lateral diagonal bracing is shown at 3 and 55 the floor-beams at 4. Vhen the second form of bridge is completed, the two tracks will be carried on the usual ties supported by four stringers, of which 5 and 0 in Fig. l forni a part of the first form of bridge, and 7 and 8 6o (shown in dotted lines) are subsequently added. While the first foi-1n of bridge is being used, the ties 9 and rails l0 are supported by the stringers 5 and G, which are placed, as shown, to leave room for swinging in the stringers 7 and 8 when the second form of bridge is to be constructed.

The rstforln of bridge, or that shown in full lines in Fig. l, differs in the following particulars from the forni it would be given if 7o intended only to serve as a single-track structure In the first place the horizontal distance between trusses must be sufficient in the clear to give rooin for accommodating two tracks of proper gage and at the proper distance apart. The floor-beams 4 must be made sufficiently strong, as indicated in the drawings, to support a double track and the live loads incident to double-track practice. The entire lateral systein is made strong enough for a two-track 8o bridge. The trusses must be made strong enough to carry the live load incident to single-track practice and the weight of the original bridge; but the connecting details for the floor-beams inust be strong enough for the double-track structure. These connecting details are shown in Fig. 3, where the end of' a floor-beam is indicated at 4 and the plates and rivets for. connecting the saine with the truss l are clearly shown. At 1l in this ig- 9o ure is shown in dotted lines the details of attachment of one of the second set of strin gers. In converting this first forni of bridge into a second form the stringere 7 and 8 are added, and the tracks are then laid over the stringers 9 5 6 and 8 on one side and 5 and 7 on the other. A second set of vertical trusses 12 is erected just outside of and parallel to the trusses l on both sides. Each of the second set of trusses is preferably connected to the correxco sponding inner truss by diaphragms 14 at proper intervals above the beams. At the lzo top and bottom the trusses 1 and 12 are further connected by stay-plates 15, and shorter stay-plates 16 are employed for connecting successive horizontal chords 17. The details of these diaphragms and stay-plates are shown in Figs. 3, fl, and 5, wherein Fig. 3 shows the attachment opposite the hoor-beams in elevation, Fig. 4 shows an elevation of the connecting means opposite the junctions of the lateral braces with the trusses, and Fig. 5 shows a plan of details of attachment at the topv of a pair of trusses 1 and 12.

It is obvious that in building our rst form of bridge the piers and abutments should be made from the first large and strong enough to accommodate our second form of bridge.

Vhat we claim is- 1. A preparatory single-track bridge having clear space enough between trusses to accommodate four stringere properly located for a two-track structure, said bridge having two longitudinal stringers so placed as to serve ultimately as the two inner stringers for the four-track road, and having a single track supported by said stringers, substantially as described.

2. In a preparatory single-track bridge,

trusses far enough apart for a double track and calculated to safely carry only the live load of a single track and the dead weight of the preparatory single-track bridge, floorbeams calculated to safely carry the doubletrack structure and connecting details between the trusses and floor-beams, also calculated to safely carry the double-track structure, substantially as described.

3. In a railway-bridge, pairs of trusses on each side,vertical diaphragms riveted to both trusses in each pair,and horizont-al stay-plates at the ends of the pairs of trusses, substantially as described.

In witness whereof we have hereunto set our hands in presence of two witnesses.

JOHN ALEXANDER LOW WADDELL. [L. s]

IRA GRANT HEDRICK. [1.. s] Vitnesses:

J. C. SANDERsoN,

J. N. GOTTFRID. 

